JPH06108137A - Method for melting low sulfur steel - Google Patents
Method for melting low sulfur steelInfo
- Publication number
- JPH06108137A JPH06108137A JP28365492A JP28365492A JPH06108137A JP H06108137 A JPH06108137 A JP H06108137A JP 28365492 A JP28365492 A JP 28365492A JP 28365492 A JP28365492 A JP 28365492A JP H06108137 A JPH06108137 A JP H06108137A
- Authority
- JP
- Japan
- Prior art keywords
- slag
- steel
- ladle
- desulfurization
- low
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は低硫鋼の溶製方法に係
り、特に取鍋炉による脱硫処理において、特別の場合を
除き電極加熱を行わず、かつ除滓を行わずして復りん、
復硫の発生しない低硫鋼の溶製方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for melting low-sulfur steel, and particularly, in the desulfurization treatment with a ladle furnace, except for special cases, electrode heating is not carried out, and dephosphorization is carried out without removing slag.
The present invention relates to a method for melting low-sulfur steel in which re-sulfurization does not occur.
【０００２】[0002]
【従来の技術】従来〔Ｓ〕≦０．００５％の低硫鋼の溶
製は一般に次の方法で行われていた。すなわち、転炉等
の精錬炉で脱炭、脱りんを完了した溶鋼を取鍋に出鋼
し、電極等をセツトして加熱可能の取鍋炉（Ｌａｄｌｅ
Ｆｕｒｎａｃｅ）とし、更に生石灰等のフラツクスの
吹込み装置を備えた２次精錬工程にて脱硫を行つてい
た。この場合２次精錬工程での復りん、復硫を防止する
ため、通常２次精錬前に除滓を行つた後、生石灰、ばん
土頁岩、螢石等の脱硫フラツクスを添加し加熱滓化して
脱硫処理する方法をとつていた。しかしながら上記従来
技術の取鍋スラグの除滓は、溶鋼温度の降下をもたらす
のみならず、除滓中に溶鋼の流出等による地金ロスがあ
り、コスト的にはきわめて不利な方法である。また除滓
後、新たに添加する脱硫フラツクスの滓化のために電極
加熱が不可欠であり、かつ滓化促進のための螢石の添加
によつて取鍋耐火物の溶損を助長する等の問題があつ
た。また一方、取鍋スラグの除滓を行わない場合には取
鍋スラグがカーボン電極によつて還元され、復りん、復
硫が発生するという新たな問題があつた。2. Description of the Related Art Conventionally, the melting of low-sulfur steel having a [S] ≦ 0.005% is generally carried out by the following method. That is, a ladle furnace (Ladle that can be heated by tapping molten steel that has been decarburized and dephosphorized in a refining furnace such as a converter into a ladle and setting electrodes and the like
Furnace) and desulfurization was carried out in the secondary refining process equipped with a device for blowing a flux such as quicklime. In this case, in order to prevent re-phosphorization and re-sulfurization in the secondary refining process, usually after removing the slag before the secondary refining, desulfurization flux such as quick lime, shale and fluorite is added to heat slag The method of desulfurization was adopted. However, the above-mentioned prior art ladle slag slag not only causes a drop in molten steel temperature, but also causes metal loss due to the outflow of molten steel during the slag, which is a very disadvantageous method in terms of cost. In addition, after slag removal, electrode heating is indispensable for the slag formation of newly added desulfurization flux, and the addition of fluorite to accelerate slag formation promotes the dissolution of ladle refractory materials. There was a problem. On the other hand, when the ladle slag is not removed, there is a new problem that the ladle slag is reduced by the carbon electrode and re-phosphorus and vulcanization occur.
【０００３】[0003]
【発明が解決しようとする課題】本発明の目的は、上記
低りん、低硫鋼製造における取鍋精錬の従来技術の問題
点に鑑み （イ）電極加熱の使用は最少限とする。 （ロ）除滓は行わない。 （ハ）復りん、復硫は発生させない。 を原則として、効果的な低硫鋼の溶製方法を提供するに
ある。SUMMARY OF THE INVENTION In view of the problems of the prior art of ladle refining in the production of low phosphorus and low sulfur steel, the object of the present invention is to (a) minimize the use of electrode heating. (B) No slag is removed. (C) Re-phosphorus and re-sulfur are not generated. In principle, it is to provide an effective method for melting low-sulfur steel.
【０００４】[0004]
【課題を解決するための手段】本発明の要旨とするとこ
ろは次の如くである。 （１）重量比にてＰ：０．０８％以下の溶銑を使用し精
錬炉で粗精錬する段階と、前記粗精錬した溶鋼を取鍋に
出鋼する段階と、前記取鍋内に出鋼した溶鋼とともに流
入したスラグ量を実測もしくは推定にて定量する段階
と、前記取鍋内のスラグ中にＡｌ滓もしくは金属Ａｌと
Ａl2Ｏ3の混合物を添加し、（Ｔ.Ｆe）＋（ＭｎＯ）の
合計量を１％以下となるまで還元する段階と、前記還元
後生石灰を添加し（ＣaＯ）／（Ａl2Ｏ3）・（ＳiＯ2）
＝０．２５〜０．３５なる脱硫スラグを形成し溶鋼の脱
硫処理を行う段階と、を有して成ることを特徴とする低
硫鋼の溶製方法。 （２）〔Ｓ〕≦０．００１％の極低硫鋼溶製の場合を除
き、精錬炉による粗精錬スラグは前記取鍋による脱硫処
理中に除滓しないことを特徴とする上記（１）に記載の
低硫鋼の溶製方法。 （３）〔Ｓ〕≦０．００１％の極低硫鋼溶製の場合を除
き、取鍋による脱硫処理中に電極等による加熱は行わな
いことを特徴とする上記（１）もしくは（２）に記載の
低硫鋼の溶製方法、である。The gist of the present invention is as follows. (1) A step of roughly refining in a refining furnace using molten iron having a weight ratio of P: 0.08% or less, a step of tapping the roughly refined molten steel in a ladle, and a tapping in the ladle. The amount of slag flowing in together with the molten steel was measured or estimated, and Al slag or a mixture of metal Al and Al 2 O 3 was added to the slag in the ladle, and (T.Fe) + (MnO ) Is reduced to a total amount of 1% or less, and after the reduction, quick lime is added (CaO) / (Al 2 O 3 ). (SiO 2 ).
= 0.25-0.35, and the step of performing desulfurization treatment of molten steel, the method for producing low-sulfur steel. (2) Except in the case of melting of [S] ≦ 0.001% ultra-low-sulfur steel, the crude smelting slag in the smelting furnace is not removed during the desulfurization treatment by the ladle. The method for producing low-sulfur steel according to 1. (3) The above (1) or (2) is characterized in that heating by an electrode or the like is not performed during desulfurization treatment with a ladle, except in the case of melting of [S] ≦ 0.001% ultra-low sulfur steel. The method for producing low-sulfur steel according to 1.
【０００５】本発明の詳細を本発明者らの実験に基いて
説明する。本発明者らは、Ｐ含有量が０．１％と高いＮ
ｏ．１溶銑と、０．０４％と比較的に低いＮｏ．２溶銑
を使用し、転炉にて精錬し、これを取鍋に出鋼した後、
約４分間の電極加熱を行って本発明による脱硫処理を行
ったが、取鍋における脱硫処理中に図１に示す如く、Ｐ
含有量の高いＮｏ．１鋼の復りんが認められたが、Ｐ含
有量の低いＮｏ．２鋼の復りんは認められなかった。し
かして復りん現象の認められない溶銑のＰ含有量の上限
がＰ：０．０８％であることが判明したので、本発明で
は使用溶銑のＰ濃度を０．０８％以下と限定した。しか
して、溶銑のＰ濃度０．０８％と平衡する転炉スラグの
Ｐ2Ｏ5濃度が１％であるので、転炉スラグのＰ2Ｏ5濃度
を１％以下に低下して取鍋精錬中における復りんを防止
した。次に取鍋内に出鋼した溶鋼とともに流入したスラ
グ量を実測もしくは推定にて定量する。これは、スラグ
中のＴ.Ｆe、ＭｎＯ、ＳiＯ2等の酸性酸化物を還元する
に要するＡｌ滓量の決定のために不可欠である。「アル
ミドロス」とも称されているＡｌ滓はスラグの改質目的
のためにコスト的にも有効な還元剤であって、ほぼ次の
ような組成を有している。 金属Ａｌ ： ３０〜５５％ Ａl2Ｏ3 １８〜４０％ ＳiＯ2 ４〜１０％ Ｔ．Ｃ ０．４〜０．８％ スラグ中のＴ.Ｆe、ＭｎＯ、ＳiＯ2等の酸性酸化物はＡ
ｌ滓に還元され次の反応により、それぞれＦｅ、Ｍｎ、
Ｓｉの金属となりＡl2Ｏ3を生成する。 ｙＭＯ＋Ａｌ→Ａl2Ｏ3＋Ｍ………………(１) ただしＭ：Ｆｅ、Ｍｎ、Ｓｉ Ａｌ滓の代りに金属Ａｌとばん土頁岩等のＡl2Ｏ3源を
使用することも可能である。The details of the present invention will be described based on experiments by the present inventors. The present inventors have found that the P content is as high as 0.1% and the N content is high.
o. No. 1 hot metal and 0.04%, which is relatively low. 2 Use hot metal, smelt in a converter, tap this in a ladle,
The electrode was heated for about 4 minutes to carry out the desulfurization treatment according to the present invention. During the desulfurization treatment in the ladle, as shown in FIG.
No. with a high content Although reconstitution of steel No. 1 was observed, No. 1 with a low P content was used. No reconstitution of steel 2 was observed. However, since it was found that the upper limit of the P content of the hot metal in which the re-phosphorus phenomenon was not observed was P: 0.08%, the P concentration of the hot metal used was limited to 0.08% or less in the present invention. Since the P 2 O 5 concentration of the converter slag that is in equilibrium with the P concentration of 0.08% of the hot metal is 1%, the P 2 O 5 concentration of the converter slag is reduced to 1% or less and ladle refining is performed. Prevents re-phosphorus inside. Next, the amount of slag that flows into the ladle together with the molten steel discharged is measured or estimated to determine the amount. This is indispensable for determining the amount of Al slag required to reduce acidic oxides such as T.Fe, MnO, and SiO 2 in slag. Al slag, which is also called "alumin dross", is a cost effective reducing agent for the purpose of modifying slag, and has the following composition. Metal Al: 30 to 55% Al 2 O 3 18 to 40% SiO 2 4 to 10% T.I. C 0.4-0.8% Acid oxides such as T.Fe, MnO, and SiO 2 in the slag are A
Fe, Mn, and
It becomes a metal of Si and produces Al 2 O 3 . yMO + Al → Al 2 O 3 + M (1) However, it is possible to use Al 2 O 3 sources such as metal Al and shale shale instead of M: Fe, Mn, Si Al slag. .
【０００６】Ａｌ滓によるスラグの還元は （Ｔ.Ｆe）＋（ＭｎＯ）≦１％..........（２） となるまで還元する。その理由は本発明者らによるＴ＝
１５８０〜１６２０℃における図２に示す脱硫スラグに
おいて、 （ＣａＯ）／｛（Ａl2Ｏ3）・（ＳiＯ2）｝＝０．２５〜
０．３５ なる条件下における（Ｓ）／［Ｓ］すなわち、鋼中のＳ
濃度［Ｓ］とスラグ中のＳ濃度（Ｓ）との分配比が高く
なる本発明による脱硫反応が有効に進行するための条件
であって、酸性酸化物の残存量が多く、（Ｔ.Ｆe）＋
（ＭｎＯ）＞１％の場合には脱硫が十分に進行しないか
らである。 本発明は、取鍋内のスラグをＡｌ滓を添加
することにより還元し、（Ｔ.Ｆe）＋（ＭｎＯ）≦１％
になったならば、還元後の（ＳiＯ2）量ならびに生成し
た（Ａl2Ｏ3）量を考慮し、これに見合う生石灰ＣａＯ
を取鍋スラグ上に添加し、（ＣａＯ）／｛（Ａl2Ｏ3）・
（ＳiＯ2）｝の値を種々変化さして、これに対応する
（Ｓ）／［Ｓ］値を測定しプロットした結果は図２に示
すとおりである。この場合（ＣａＯ）／｛（Ａl2Ｏ3）・
（ＳiＯ2）｝の値が０．２５未満の場合は塩基度（Ｃａ
Ｏ）／（ＳiＯ2）が低下して脱硫反応が阻害され、また
この値が０．３５を越える場合はスラグの融点が上昇し
て滓化が不安定となり、脱硫も不安定となる。従って
（Ｓ）／［Ｓ］が最大となる場合の （ＣａＯ）／｛（Ａl2Ｏ3）・（ＳiＯ2）｝＝０．２５〜０．３５…………（３） と限定するスラグ成分を最終脱硫スラグとする。The reduction of slag with Al slag is performed until (T.Fe) + (MnO) ≦ 1% ........ (2). The reason is that T =
In the desulfurization slag shown in FIG. 2 at 1580 to 1620 ° C., (CaO) / {(Al 2 O 3 ). (SiO 2 )} = 0.25 to
(S) / [S] under the condition of 0.35, that is, S in steel
This is a condition for effectively promoting the desulfurization reaction according to the present invention in which the distribution ratio between the concentration [S] and the S concentration (S) in the slag is high, and a large amount of the acidic oxide remains (T.Fe ) +
This is because desulfurization does not proceed sufficiently when (MnO)> 1%. The present invention reduces the slag in the ladle by adding Al slag, (T.Fe) + (MnO) ≦ 1%
If it becomes, the amount of (SiO 2 ) after reduction and the amount of (Al 2 O 3 ) formed are taken into consideration, and quick lime CaO that corresponds to this
Add ladle slag to (CaO) / {(Al 2 O 3 ) ・
The values of (SiO 2 )} are variously changed, the corresponding (S) / [S] values are measured and plotted, and the results are shown in FIG. In this case (CaO) / {(Al 2 O 3 ) ・
If the value of (SiO 2 )} is less than 0.25, the basicity (Ca
O) / (SiO 2 ) decreases and the desulfurization reaction is hindered, and when this value exceeds 0.35, the melting point of the slag rises and slag formation becomes unstable, and desulfurization also becomes unstable. Therefore, when (S) / [S] is maximum, (CaO) / {(Al 2 O 3 ) · (SiO 2 )} = 0.25 to 0.35 ............ (3) The component is the final desulfurization slag.
【０００７】上記本発明による脱硫反応は取鍋中におけ
る電極加熱は必要最少限とし、(１)式による反応熱を利
用し、最終工程で添加するＣaＯの滓化促進も電極によ
る加熱を必要とせず、また滓化促進のために螢石の添加
も必要としない。なお、本発明において酸性酸化物スラ
グの還元に用いるＡl滓もしくは金属Ａｌ滓とＡl2Ｏ3の
Ａl2Ｏ3源としては、ばん土頁岩を有効に利用すること
ができる。また本発明における転炉等の精錬炉からのス
ラグの除滓は、〔Ｓ〕≦0.001％の極低硫鋼溶製の場合
を除き必要としないので、これによる溶鋼温度の低下は
避けることができる。ただし、〔Ｓ〕≦０．００１％の
極低硫鋼溶製の場合は、転炉等の精錬炉からの出鋼時の
流出スラグの除滓を行つた後、Ａl滓による酸性酸化物
の還元後、生石灰の添加を行い、（ＣaＯ）／｛（Ａl2
Ｏ3）・（ＳiＯ2）｝＝０.２５〜０.３５の脱硫スラグを
造ってもよい。この場合のＡlの酸化源としては大気に
より溶鋼が再酸化して生成したＦｅＯのほか、残留スラ
グ中のＦｅＯ、溶鋼中の〔Ａl〕と平衡する鋼中の遊離
酸素があり、Ａl滓は十分滓化される。従つてＡl酸化に
よる反応熱を利用して添加生石灰は十分に滓化される。In the desulfurization reaction according to the present invention, the electrode heating in the ladle is set to the minimum necessary, and the heat of reaction according to the equation (1) is used to promote the slag formation of CaO added in the final step, which requires the heating by the electrode. In addition, addition of fluorite to accelerate slag formation is not required. As the Al 2 O 3 source of Al slag or metal Al dross and Al 2 O 3 for use in the reduction of the acidic oxide slag in the present invention, bands shale can be effectively utilized. Further, since the removal of slag from a refining furnace such as a converter in the present invention is not required except for the production of [S] ≤ 0.001% ultra-low sulfur steel, a decrease in molten steel temperature due to this can be avoided. it can. However, in the case of melting [S] ≤ 0.001% ultra-low-sulfur steel, after removing the slag that has flowed out of the refining furnace such as a converter, the acid slag produced by Al slag is removed. After reduction, quick lime was added, and (CaO) / {(Al 2
O 3) · (or building a desulfurization slag of SiO 2)} = 0.25~0.35. In this case, the sources of Al oxidation include FeO generated by reoxidation of molten steel by the atmosphere, FeO in the residual slag, and free oxygen in the steel in equilibrium with [Al] in the molten steel. Be slagged. Therefore, the added quicklime is sufficiently slagged by utilizing the heat of reaction due to Al oxidation.
【０００８】[0008]
【実施例】Ｐ≦０．０８％以下の溶銑を使用し、転炉で
粗精錬を行つた後、転炉流出スラグの除滓を行う場合、
行わない場合、および酸性酸化物をＡl滓にて還元した
後、生石灰を添加時に同時にばん土頁岩を使用する等Ｎ
ｏ．１、Ｎｏ．２、Ｎｏ．３の本発明による脱硫処理を
行い、結果を比較する比較試験を行つた。 供試鋼Ｎｏ．１：転炉から取鍋に出鋼後電極加熱を行わ
ず直ちにＡl滓による酸性酸化物の還元を行い、（Ｔ.Ｆ
e）+（ＭnＯ）≦１％とした後、ＣaＯを添加して （ＣaＯ）／｛（Ａl2Ｏ3）・（ＳiＯ2）｝＝０．２５〜
０．３５ なる脱硫スラグを形成して脱硫した結果、図３のＮｏ．
１に示す如く取鍋内処理時間の経過と共に脱硫して、最
終的にＳ：０．０１２％の低硫鋼を得た。この場合の生
石灰の滓化はすべてＡl滓による還元反応熱を利用した
もので、取鍋に付属の電極による加熱は全く行わなかつ
た。[Example] When the molten iron with P ≦ 0.08% or less is used and the slag of the converter outflow slag is removed after the coarse refining is performed in the converter,
If not, and after reducing the acidic oxides with Al slag, use quick clay shale at the same time when adding quick lime.
o. 1, No. 2, No. 3 desulfurization treatments according to the present invention were performed, and comparative tests were conducted to compare the results. Test steel No. 1: Immediately after tapping the ladle from the converter to the ladle, the electrode oxide was not heated and the acid oxide was immediately reduced by the Al slag.
e) + (MnO) ≦ 1%, and then CaO is added to add (CaO) / {(Al 2 O 3 ). (SiO 2 )} = 0.25
As a result of desulfurization by forming desulfurization slag of 0.35, No. 3 in FIG.
As shown in FIG. 1, desulfurization was performed with the lapse of the processing time in the ladle, and finally low-sulfur steel with S: 0.012% was obtained. In this case, quick lime slag was all converted by utilizing the heat of reduction reaction by Al slag, and heating by the electrode attached to the ladle was not performed at all.
【０００９】供試鋼Ｎｏ．２ 転炉による出鋼を取鍋に収容した後、除滓を行つた。除
滓後ばん土頁岩を添加すると共に電極を降下して約６分
間加熱し、滓化を図った。次にＡl滓を計算量添加して
（Ｔ・Ｆｅ）＋（ＭｎＯ）≦１％とした後、生石灰を添
加し （ＣaＯ）／｛（Ａl2Ｏ3）・（ＳiＯ2）｝＝０．２５〜
０．３５ の脱硫スラグを形成して脱硫した結果、図１に示される
如く約１９分の取鍋精錬時間の経過と共に脱硫され、最
終的にＳ：０．００１％の極低硫鋼を得た。Specimen steel No. 2 After putting the tapped steel from the converter into a ladle, the slag was removed. After removing the slag, the soil shale was added and the electrode was lowered and heated for about 6 minutes to slag. Next, after adding a calculated amount of Al slag to (T · Fe) + (MnO) ≦ 1%, quicklime was added (CaO) / {(Al 2 O 3 ) · (SiO 2 )} = 0. 25-
As a result of desulfurization by forming desulfurization slag of 0.35, as shown in Fig. 1, it was desulfurized with the elapse of the ladle refining time of about 19 minutes, and finally S: 0.001% of ultra low sulfur steel was obtained. It was
【００１０】供試鋼Ｎｏ.３ Ｎｏ．２と同様に転炉出鋼を取鍋に収容した後、除滓せ
ずに直ちに電極を降下して約６分間の加熱を行い、同時
にばん土頁岩を添加して、これを滓化した。その後Ａl
滓を添加して （Ｔ・Ｆｅ）＋（ＭｎＯ）≦１％ となるまで還元し、その後生石灰を添加して （ＣaＯ）／｛（Ａl2Ｏ3）・（ＳiＯ2）｝＝０．２５〜
０．３５ なる脱硫スラグを形成した。この１９分間の取鍋精錬時
間の経過と共に脱硫され、最終脱硫スラグによる低硫鋼
のＳ濃度は、図１におけるＮｏ．３曲線の示す如く０．
００３％の低硫鋼を得た。Test Steel No. 3 No. After the converter tapped steel was placed in a ladle in the same manner as in 2, the electrode was immediately lowered and heated for about 6 minutes without slag removal, and at the same time, shale shale was added and slagged. Then Al
Add slag to reduce until (T · Fe) + (MnO) ≦ 1%, then add quick lime (CaO) / {(Al 2 O 3 ) · (SiO 2 )} = 0.25 ~
A desulfurization slag of 0.35 was formed. The S concentration of the low-sulfur steel that has been desulfurized with the lapse of this ladle refining time of 19 minutes, and the final desulfurized slag has a S concentration of No. 1 in FIG. As shown by the three curves, 0.
003% low-sulfur steel was obtained.
【００１１】[0011]
【発明の効果】本発明による低硫鋼の溶製方法は、従来
採られて来た取鍋炉による電極加熱、フラツクス吹込み
の脱硫方法の欠点を克服し、極低硫鋼の溶製時以外は通
常転炉等の一次精錬炉のスラグを除滓せず、また電極加
熱も全く行わないか、もしくは数分間のきわめて短時間
に抑制し、取鍋内にＡl滓もしくは金属アルミニウムと
ばん土頁岩のＡl2Ｏ3源を添加することにより、スラグ
中の酸性酸化物を還元した後、生石灰を吹込み （ＣaＯ）／｛（Ａl2Ｏ3）・（ＳiＯ2）｝＝０．２５〜
０．３５ の脱硫スラグを形成し、溶鋼を脱硫する方法をとつたの
で、次の効果を挙げることができた。 （イ）本発明では使用溶銑のＰ含有量を０．０８％以下
に限定したので、取鍋による脱硫の２次精錬途中におい
ても復りんすることがない。 （ロ）１次精錬炉のスラグをほとんど除滓しない方法を
とつたので溶鋼温度の低減を防止し得た。 （ハ）スラグ中の酸性酸化物の還元にＡl滓を使用する
ので、効果的であるほか、コスト面でも有利である。 （ニ）強力な脱硫スラグを形成するのでＳ＝０．００１
％までの脱硫が可能である。 （ホ）最終脱硫スラグ形成の生石灰の滓化も、電極加熱
によらずＡl滓による反応熱を利用し得るので、螢石等
の滓化促進剤の添加を要しない。この結果脱硫処理中の
復りん、復硫が全くなく、かつ取鍋耐火物の原単位の低
減、ひいてはコストの低減が可能となつた。EFFECT OF THE INVENTION The method for producing low-sulfur steel according to the present invention overcomes the disadvantages of the conventional desulfurization methods of heating an electrode by a ladle furnace and blowing a flux, except for the production of ultra-low-sulfur steel. Does not usually remove slag from primary refining furnaces such as converters, does not perform electrode heating at all, or suppresses it for a very short time of a few minutes, so that Al slag or metallic aluminum and shale in the ladle Al 2 O 3 source is added to reduce the acidic oxide in the slag, and then lime is blown into it (CaO) / {(Al 2 O 3 ). (SiO 2 )} = 0.25
Since the desulfurization slag of 0.35 was formed and the molten steel was desulfurized, the following effects could be obtained. (A) In the present invention, since the P content of the hot metal used is limited to 0.08% or less, re-phosphorization does not occur even during the secondary refining of desulfurization with a ladle. (B) Since the slag of the primary refining furnace was hardly removed, the molten steel temperature could be prevented from lowering. (C) Since Al slag is used for the reduction of the acidic oxides in the slag, it is effective and cost effective. (D) S = 0.001 because a strong desulfurization slag is formed.
% Desulfurization is possible. (E) The slag formation of quick lime for the final desulfurization slag formation can utilize the reaction heat of the Al slag without depending on the electrode heating, and thus does not require addition of a slag formation accelerator such as fluorite. As a result, there was no re-phosphorization or re-sulfurization during desulfurization treatment, and it was possible to reduce the basic unit of ladle refractory, and consequently the cost.
【図１】取鍋による２次精錬中における復りんに及ぼす
使用溶銑中のＰ含有量の影響を調査する実験におけるＰ
含有量０．１％の溶銑を使用した供試鋼Ｎｏ．１と、Ｐ
含有量０．０４％の溶銑を使用した供試鋼Ｎｏ．２の取
鍋による脱硫処理中におけるＰ含有量の変化を示す線図
である。FIG. 1 P in an experiment investigating the effect of P content in hot metal used on re-phosphorus during secondary refining with a ladle
Test steel No. using hot metal with a content of 0.1% 1 and P
Test steel No. using hot metal with a content of 0.04% It is a diagram which shows the change of P content in the desulfurization process by the ladle of FIG.
【図２】取鍋による脱硫処理の２次精錬中におけるスラ
グの（Ｔ．Ｆｅ）＋（ＭｎＯ）≦１、Ｔ＝１５８０〜１
６２０℃のもとで、(ＣaＯ)／｛(Ａl2Ｏ3)・(ＳiＯ2)｝
を０．１から０．５まで変化させた時のＳの分配比
（Ｓ）／〔Ｓ〕に及ぼす影響を示す線図である。FIG. 2 (T.Fe) + (MnO) ≦ 1, T = 1580-1 of slag during secondary refining in desulfurization treatment with ladle
At 620 ° C, (CaO) / {(Al 2 O 3 ) ・ (SiO 2 )}
It is a diagram which shows the influence which it has on distribution ratio (S) / [S] of S when changing from 0.1 to 0.5.
【図３】本発明の実施例における供試鋼Ｎｏ．１、Ｎ
ｏ．２、Ｎｏ．３の取鍋による脱硫処理時間の経過に伴
う鋼中Ｓ含有量〔Ｓ〕／１００3％の変化を示す線図で
あつて、 Ｎｏ．１ 除滓なし Ａl滓使用の場合 Ｎｏ．２ 除滓実施 ばん土頁岩使用の場合 Ｎｏ．３ 除滓なし ばん土頁岩使用の場合FIG. 3 is a test steel No. in the example of the present invention. 1, N
o. 2, No. 3 is a diagram showing changes in the S content [S] / 100 3 % in steel with the lapse of desulfurization treatment time by the ladle of No. 3; No slag 1 When using Al slag No. 2 Debris implementation When using shale shale No. 3 When using shale without slag
Claims (3)
使用し精錬炉で粗精錬する段階と、前記粗精錬した溶鋼
を取鍋に出鋼する段階と、前記取鍋内に出鋼した溶鋼と
ともに流入したスラグ量を実測もしくは推定にて定量す
る段階と、前記取鍋内のスラグ中にＡｌ滓もしくは金属
ＡｌとＡl2Ｏ3の混合物を添加し、（Ｔ、Ｆｅ）＋（Ｍ
ｎＯ）の合計量を１％以下となるまで還元する段階と、
前記還元後生石灰を添加し （ＣaＯ）／｛（Ａl2Ｏ3）・（ＳiＯ2）｝＝０．２５〜
０．３５ なる脱硫スラグを形成し溶鋼の脱硫処理を行う段階と、
を有することを特徴とする低硫鋼の溶製方法。1. A step of roughly refining in a refining furnace using molten pig iron with a weight ratio of P: 0.08% or less, a step of tapping the roughly refined molten steel in a ladle, and a step of A step of quantitatively measuring or estimating the amount of slag that has flowed in together with the molten steel that has been tapped, adding Al slag or a mixture of metallic Al and Al 2 O 3 to the slag in the ladle, and adding (T, Fe) + (M
reducing the total amount of nO) to 1% or less,
After the reduction, quick lime was added, and (CaO) / {(Al 2 O 3 ). (SiO 2 )} = 0.25-
Forming a desulfurization slag of 0.35 and performing desulfurization treatment of molten steel;
And a method for melting low-sulfur steel.
合を除き、精錬炉による粗精錬スラグは前記取鍋による
脱硫処理中に除滓しないことを特徴とする請求項１に記
載の低硫鋼の溶製方法。2. Except in the case of melting of [S] ≦ 0.001% ultra-low sulfur steel, the crude smelting slag in the smelting furnace is not removed during the desulfurization treatment by the ladle. 1. The method for melting low-sulfur steel according to 1.
合を除き、取鍋による脱硫処理中に電極等による加熱は
行わないことを特徴とする請求項（１）もしくは（２）
に記載の低硫鋼の溶製方法。3. The method according to claim 1, wherein heating by an electrode or the like is not carried out during the desulfurization treatment with a ladle, except in the case of melting [S] ≦ 0.001% of extremely low-sulfur steel. (2)
The method for producing low-sulfur steel according to 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28365492A JPH06108137A (en) | 1992-09-29 | 1992-09-29 | Method for melting low sulfur steel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28365492A JPH06108137A (en) | 1992-09-29 | 1992-09-29 | Method for melting low sulfur steel |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH06108137A true JPH06108137A (en) | 1994-04-19 |
Family
ID=17668330
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP28365492A Pending JPH06108137A (en) | 1992-09-29 | 1992-09-29 | Method for melting low sulfur steel |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH06108137A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000212633A (en) * | 1999-01-28 | 2000-08-02 | Kawasaki Steel Corp | Desulfurization of molten steel in ladle refining |
| KR100398395B1 (en) * | 1999-10-13 | 2003-09-19 | 주식회사 포스코 | A method for desulfurizing the molten steel in the mini-mill process |
| CN104818364A (en) * | 2015-04-29 | 2015-08-05 | 江苏大学 | Slag accretion agent for ladle furnace slagging and refining, and preparation method and application method thereof |
| CN115505667A (en) * | 2022-09-19 | 2022-12-23 | 首钢集团有限公司 | KR powder injection molten iron pretreatment method |
-
1992
- 1992-09-29 JP JP28365492A patent/JPH06108137A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000212633A (en) * | 1999-01-28 | 2000-08-02 | Kawasaki Steel Corp | Desulfurization of molten steel in ladle refining |
| KR100398395B1 (en) * | 1999-10-13 | 2003-09-19 | 주식회사 포스코 | A method for desulfurizing the molten steel in the mini-mill process |
| CN104818364A (en) * | 2015-04-29 | 2015-08-05 | 江苏大学 | Slag accretion agent for ladle furnace slagging and refining, and preparation method and application method thereof |
| CN115505667A (en) * | 2022-09-19 | 2022-12-23 | 首钢集团有限公司 | KR powder injection molten iron pretreatment method |
| CN115505667B (en) * | 2022-09-19 | 2023-09-15 | 首钢集团有限公司 | KR powder spraying molten iron pretreatment method |
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